About frequency distribution

2. FREQUENCY DISTRIBUTION
TABLE

3. WHAT IS FREQUENCY?
Frequency is the number of times an observation
or a particular value appears in a data set.
WHAT IS FREQUENCY DISTRIBUTION TABLE?
It is a systematics way of presenting data using a
table.

4. Two types of frequency distribution
Ungrouped frequency distribution
-classifies a given data set(usually n<30) under
a specific category or class.
Grouped frequency distribution
- having an interval or ratio-level data and
beyond a sample size of 30.

5. Ungrouped frequency Grouped frequency
distribution distribution
distribution
AGE TALLY FREQUENCY
19
18
17
16
15
CLASS
INTERVAL
TALLY FREQUENCY
95-99
90-94
85-89
80-84
75-79

6. Ungrouped Frequency
Distribution
Twenty-five positive cases of COVID-19 were given
a blood tests to determine their blood type. The
data set is as follows:
A B B AB O
O O B AB B
B B O A O
A O O O AB
AB A O B A

7. Definitions
Range- a measure of spread in Statistics. It is the
difference between the greatest value and the least value
in a set of numerical data.
Class Interval- number of classes
Class size- obtained by dividing the range by the class
interval
Lower Limit- the smallest value in the class
Upper Limit- the highest value in the class

8. Example of Grouped Frequency Distribution
The following are test scores of section 1. Construct a
suitable frequency table. Use 6 as the number of classes.
14 15 30 19 10 18
26 30 10 15 15 28
10 30 34 40 20 43
20 30 10 22 36 36

9. Steps in constructing a grouped frequency distribution
table.
Step 1. Find the range.=highest value – lower value
Step 2. decide on the number of classes(usually 5-20).
=2^k˃n
where k = unknown number; n= total number of
correspondent
Step 3. Solve the class width or class size by dividing the
range by the number of classes or intervals

10. Step 4. Add the class width to the starting point to
get the second lower class limit. Then enter the
upper class limit.
Step 5. represent each score by a tally and count the
total frequency of each class.

11. •Another example:
•The following are test scores of
section 1. Construct a suitable
frequency table. Use 6 as the
number of classes.
• 14 15 30 19 10 18
• 26 30 10 15 15 28
• 10 30 34 40 20 43
• 20 30 10 22 36 36
1. Number of classes or
interval-6
2. Range = H - L
= 43 -10
=33
3. Class size = R/i
=33/6
= 5.5 or
6

12. By group activity
Grades of 40 students in math
SCORES TALLY FREQUENCY
95-99 III 3
90-94 IIII 5
85-89 IIII-IIII 9
80-84 IIII-IIII-III 13
75-79 IIII 4
70-74 IIII-I 6

13. Answer the following: ( 5 pts. each)
1. How many class intervals are there?
2. What is the lowest class interval? Highest class
interval?
3. What is the class size?
4. Which score interval has the highest frequency?
Lowest frequency?

14. Direction: Make a frequency distribution table using
the data below.
Jessica is a “plantita”, she surveyed twenty
households in their barangay and found out the
number of varieties of plants they own. The results
are:
3, 0, 1, 4, 4, 1, 2, 0, 2, 2, 0, 2, 0, 1, 3, 1, 2, 1, 1,
3

15. Assignment
The following shows the intelligence quotient (IQ) of 20
students. Construct the frequency distribution using 6
intervals.
97 90 92 91 92
92 87 100 97 98
101 110 98 93 95
100 93 91 98 105

16. Thank you for listening